TOKYO - Japan moved closer Thursday to restarting nuclear reactors for the first time since last year's earthquake and tsunami led to a nationwide shutdown after a mayor gave his support to a plan to bring two of them back online.

All 50 of Japan's workable reactors are offline because of safety concerns or for maintenance since the March 11 disaster touched off a crisis at the Fukushima Dai-ichi plant. Public opposition to nuclear power remains high, even though the government has been pressing for the restart of reactors because it says nuclear energy is crucial to Japan's economy.

Power companies have warned of shortages in the months ahead, as demand reaches its summer peak.

Work to restart two reactors in the western town of Ohi, which are the first ready to resume generating power, could begin as soon as this weekend now that the mayor signed off on the plan. Once the work begins, it takes about three weeks to get a reactor operating at full capacity.

The governor of Fukui, the prefecture (state) in which Ohi is located, now has to meet with Prime Minister Yoshihiko Noda to inform him that the local governments are willing to accept the restart plan. The prime minister has to give final approval, which Japanese media reports said will likely happen Saturday.

"We want to move ahead as quickly as possible once we receive the approval," said Takahiro Senoo, a spokesman for Kansai Electric Power Co., the utility that runs the plant. He said that if work is begun soon the plant could be up and running in time to meet the summer crunch, which is expected in mid-July or August.

Ohi Mayor Shinobu Tokioka said he approved the plan because he is concerned about possible power shortages and the impact on the local economy of keeping the plant closed.

Local consent is not legally required for restarting the reactors, but the government wants the support because of the sensitivity of the issue. The public has shown great concern that government failures, such as not sharing radiation leak data, worsened the crisis at Fukushima and may recur.

Last year's massive earthquake and tsunami caused explosions and meltdowns at the Fukushima plant, which is north of Tokyo. Tens of thousands of residents were evacuated because of the radiation leaks. Although the plant's operator says it has restored some stability, it could take years to decontaminate the area and decades to safely close down Fukushima's reactors.

With the high-demand summer months looming, Noda announced last week that he wants to restart Ohi's reactors as soon as possible. He also said he wants to move forward with the restart of other plants as soon as their safety is confirmed.

Before last year's crisis, Japan depended on nuclear for about one-third of its electricity and was planning to expand that further. The government is now carrying out a sweeping review of that plan.

Noda said the government has taken ample measures to ensure the two reactors in Fukui prefecture would not leak radiation if an earthquake or tsunami as severe as last year's should strike them.